| /* |
| * Kernel support for the ptrace() and syscall tracing interfaces. |
| * |
| * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc. |
| * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx> |
| * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org> |
| * Copyright (C) 2008 Helge Deller <deller@gmx.de> |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/sched.h> |
| #include <linux/mm.h> |
| #include <linux/smp.h> |
| #include <linux/errno.h> |
| #include <linux/ptrace.h> |
| #include <linux/tracehook.h> |
| #include <linux/user.h> |
| #include <linux/personality.h> |
| #include <linux/security.h> |
| #include <linux/seccomp.h> |
| #include <linux/compat.h> |
| #include <linux/signal.h> |
| #include <linux/audit.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/pgtable.h> |
| #include <asm/processor.h> |
| #include <asm/asm-offsets.h> |
| |
| /* PSW bits we allow the debugger to modify */ |
| #define USER_PSW_BITS (PSW_N | PSW_B | PSW_V | PSW_CB) |
| |
| /* |
| * Called by kernel/ptrace.c when detaching.. |
| * |
| * Make sure single step bits etc are not set. |
| */ |
| void ptrace_disable(struct task_struct *task) |
| { |
| clear_tsk_thread_flag(task, TIF_SINGLESTEP); |
| clear_tsk_thread_flag(task, TIF_BLOCKSTEP); |
| |
| /* make sure the trap bits are not set */ |
| pa_psw(task)->r = 0; |
| pa_psw(task)->t = 0; |
| pa_psw(task)->h = 0; |
| pa_psw(task)->l = 0; |
| } |
| |
| /* |
| * The following functions are called by ptrace_resume() when |
| * enabling or disabling single/block tracing. |
| */ |
| void user_disable_single_step(struct task_struct *task) |
| { |
| ptrace_disable(task); |
| } |
| |
| void user_enable_single_step(struct task_struct *task) |
| { |
| clear_tsk_thread_flag(task, TIF_BLOCKSTEP); |
| set_tsk_thread_flag(task, TIF_SINGLESTEP); |
| |
| if (pa_psw(task)->n) { |
| struct siginfo si; |
| |
| /* Nullified, just crank over the queue. */ |
| task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1]; |
| task_regs(task)->iasq[0] = task_regs(task)->iasq[1]; |
| task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4; |
| pa_psw(task)->n = 0; |
| pa_psw(task)->x = 0; |
| pa_psw(task)->y = 0; |
| pa_psw(task)->z = 0; |
| pa_psw(task)->b = 0; |
| ptrace_disable(task); |
| /* Don't wake up the task, but let the |
| parent know something happened. */ |
| si.si_code = TRAP_TRACE; |
| si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3); |
| si.si_signo = SIGTRAP; |
| si.si_errno = 0; |
| force_sig_info(SIGTRAP, &si, task); |
| /* notify_parent(task, SIGCHLD); */ |
| return; |
| } |
| |
| /* Enable recovery counter traps. The recovery counter |
| * itself will be set to zero on a task switch. If the |
| * task is suspended on a syscall then the syscall return |
| * path will overwrite the recovery counter with a suitable |
| * value such that it traps once back in user space. We |
| * disable interrupts in the tasks PSW here also, to avoid |
| * interrupts while the recovery counter is decrementing. |
| */ |
| pa_psw(task)->r = 1; |
| pa_psw(task)->t = 0; |
| pa_psw(task)->h = 0; |
| pa_psw(task)->l = 0; |
| } |
| |
| void user_enable_block_step(struct task_struct *task) |
| { |
| clear_tsk_thread_flag(task, TIF_SINGLESTEP); |
| set_tsk_thread_flag(task, TIF_BLOCKSTEP); |
| |
| /* Enable taken branch trap. */ |
| pa_psw(task)->r = 0; |
| pa_psw(task)->t = 1; |
| pa_psw(task)->h = 0; |
| pa_psw(task)->l = 0; |
| } |
| |
| long arch_ptrace(struct task_struct *child, long request, |
| unsigned long addr, unsigned long data) |
| { |
| unsigned long tmp; |
| long ret = -EIO; |
| |
| switch (request) { |
| |
| /* Read the word at location addr in the USER area. For ptraced |
| processes, the kernel saves all regs on a syscall. */ |
| case PTRACE_PEEKUSR: |
| if ((addr & (sizeof(unsigned long)-1)) || |
| addr >= sizeof(struct pt_regs)) |
| break; |
| tmp = *(unsigned long *) ((char *) task_regs(child) + addr); |
| ret = put_user(tmp, (unsigned long __user *) data); |
| break; |
| |
| /* Write the word at location addr in the USER area. This will need |
| to change when the kernel no longer saves all regs on a syscall. |
| FIXME. There is a problem at the moment in that r3-r18 are only |
| saved if the process is ptraced on syscall entry, and even then |
| those values are overwritten by actual register values on syscall |
| exit. */ |
| case PTRACE_POKEUSR: |
| /* Some register values written here may be ignored in |
| * entry.S:syscall_restore_rfi; e.g. iaoq is written with |
| * r31/r31+4, and not with the values in pt_regs. |
| */ |
| if (addr == PT_PSW) { |
| /* Allow writing to Nullify, Divide-step-correction, |
| * and carry/borrow bits. |
| * BEWARE, if you set N, and then single step, it won't |
| * stop on the nullified instruction. |
| */ |
| data &= USER_PSW_BITS; |
| task_regs(child)->gr[0] &= ~USER_PSW_BITS; |
| task_regs(child)->gr[0] |= data; |
| ret = 0; |
| break; |
| } |
| |
| if ((addr & (sizeof(unsigned long)-1)) || |
| addr >= sizeof(struct pt_regs)) |
| break; |
| if ((addr >= PT_GR1 && addr <= PT_GR31) || |
| addr == PT_IAOQ0 || addr == PT_IAOQ1 || |
| (addr >= PT_FR0 && addr <= PT_FR31 + 4) || |
| addr == PT_SAR) { |
| *(unsigned long *) ((char *) task_regs(child) + addr) = data; |
| ret = 0; |
| } |
| break; |
| |
| default: |
| ret = ptrace_request(child, request, addr, data); |
| break; |
| } |
| |
| return ret; |
| } |
| |
| |
| #ifdef CONFIG_COMPAT |
| |
| /* This function is needed to translate 32 bit pt_regs offsets in to |
| * 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel |
| * will request offset 12 if it wants gr3, but the lower 32 bits of |
| * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4). |
| * This code relies on a 32 bit pt_regs being comprised of 32 bit values |
| * except for the fp registers which (a) are 64 bits, and (b) follow |
| * the gr registers at the start of pt_regs. The 32 bit pt_regs should |
| * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[] |
| * being 64 bit in both cases. |
| */ |
| |
| static compat_ulong_t translate_usr_offset(compat_ulong_t offset) |
| { |
| if (offset < 0) |
| return sizeof(struct pt_regs); |
| else if (offset <= 32*4) /* gr[0..31] */ |
| return offset * 2 + 4; |
| else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */ |
| return offset + 32*4; |
| else if (offset < sizeof(struct pt_regs)/2 + 32*4) |
| return offset * 2 + 4 - 32*8; |
| else |
| return sizeof(struct pt_regs); |
| } |
| |
| long compat_arch_ptrace(struct task_struct *child, compat_long_t request, |
| compat_ulong_t addr, compat_ulong_t data) |
| { |
| compat_uint_t tmp; |
| long ret = -EIO; |
| |
| switch (request) { |
| |
| case PTRACE_PEEKUSR: |
| if (addr & (sizeof(compat_uint_t)-1)) |
| break; |
| addr = translate_usr_offset(addr); |
| if (addr >= sizeof(struct pt_regs)) |
| break; |
| |
| tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr); |
| ret = put_user(tmp, (compat_uint_t *) (unsigned long) data); |
| break; |
| |
| /* Write the word at location addr in the USER area. This will need |
| to change when the kernel no longer saves all regs on a syscall. |
| FIXME. There is a problem at the moment in that r3-r18 are only |
| saved if the process is ptraced on syscall entry, and even then |
| those values are overwritten by actual register values on syscall |
| exit. */ |
| case PTRACE_POKEUSR: |
| /* Some register values written here may be ignored in |
| * entry.S:syscall_restore_rfi; e.g. iaoq is written with |
| * r31/r31+4, and not with the values in pt_regs. |
| */ |
| if (addr == PT_PSW) { |
| /* Since PT_PSW==0, it is valid for 32 bit processes |
| * under 64 bit kernels as well. |
| */ |
| ret = arch_ptrace(child, request, addr, data); |
| } else { |
| if (addr & (sizeof(compat_uint_t)-1)) |
| break; |
| addr = translate_usr_offset(addr); |
| if (addr >= sizeof(struct pt_regs)) |
| break; |
| if (addr >= PT_FR0 && addr <= PT_FR31 + 4) { |
| /* Special case, fp regs are 64 bits anyway */ |
| *(__u64 *) ((char *) task_regs(child) + addr) = data; |
| ret = 0; |
| } |
| else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) || |
| addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 || |
| addr == PT_SAR+4) { |
| /* Zero the top 32 bits */ |
| *(__u32 *) ((char *) task_regs(child) + addr - 4) = 0; |
| *(__u32 *) ((char *) task_regs(child) + addr) = data; |
| ret = 0; |
| } |
| } |
| break; |
| |
| default: |
| ret = compat_ptrace_request(child, request, addr, data); |
| break; |
| } |
| |
| return ret; |
| } |
| #endif |
| |
| long do_syscall_trace_enter(struct pt_regs *regs) |
| { |
| /* Do the secure computing check first. */ |
| secure_computing_strict(regs->gr[20]); |
| |
| if (test_thread_flag(TIF_SYSCALL_TRACE) && |
| tracehook_report_syscall_entry(regs)) { |
| /* |
| * Tracing decided this syscall should not happen or the |
| * debugger stored an invalid system call number. Skip |
| * the system call and the system call restart handling. |
| */ |
| regs->gr[20] = -1UL; |
| goto out; |
| } |
| |
| #ifdef CONFIG_64BIT |
| if (!is_compat_task()) |
| audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25], |
| regs->gr[24], regs->gr[23]); |
| else |
| #endif |
| audit_syscall_entry(regs->gr[20] & 0xffffffff, |
| regs->gr[26] & 0xffffffff, |
| regs->gr[25] & 0xffffffff, |
| regs->gr[24] & 0xffffffff, |
| regs->gr[23] & 0xffffffff); |
| |
| out: |
| return regs->gr[20]; |
| } |
| |
| void do_syscall_trace_exit(struct pt_regs *regs) |
| { |
| int stepping = test_thread_flag(TIF_SINGLESTEP) || |
| test_thread_flag(TIF_BLOCKSTEP); |
| |
| audit_syscall_exit(regs); |
| |
| if (stepping || test_thread_flag(TIF_SYSCALL_TRACE)) |
| tracehook_report_syscall_exit(regs, stepping); |
| } |